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Coordinate Geometry Videos 28 videos
ACT Math: Coordinate Geometry Drill 1, Problem 1. Which inequality is expressed by the number line?
ACT Math: Coordinate Geometry Drill 3, Problem 3. What is the standard form equation for the line?
ACT Math: Coordinate Geometry Drill 2, Problem 4. What is the equation for the circle in the video?
ACT Math 5.3 Coordinate Geometry 436 Views
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Description:
ACT Math: Coordinate Geometry Drill 5, Problem 3. Graph the inequality.
Transcript
- 00:02
Here's another shmoop du jour...
- 00:05
Graph the inequality -4 ≤ -2x < 6.
- 00:10
And here are your potential answers...
- 00:14
As with all of these kinds of problems, there
- 00:17
are really two inequalities here...the first is: negative 4 is less than or equal to negative 2x.
Full Transcript
- 00:23
To isolate x we need to divide both sides by negative 2...
- 00:23
To isolate x we need to divide both sides by negative 2 and… a red light should be
- 00:27
Whenever we divide or multiply an inequality by a negative, we have to flip the sideways
- 00:31
ice cream cone once
- 00:32
around...x is less than or equal to 2.
- 00:35
Well, we have a starting point.
- 00:37
On our number line we mark the 2... and since it's less than OR equal to, it means that
- 00:43
the dot has to be filled in...
- 00:46
So B and C don't work... and neither does A, which starts at 3 rather than 2.
- 00:50
We know that x is LESS than 2, meaning that it's gonna live somewhere
- 00:54
over here...
- 00:55
The only one left that might work is D... but just to be sure let's check out the 2nd
- 00:59
part of the equation.
- 01:00
We have negative 2x is less than 6... Divide both sides by negative 2, flip around
- 01:06
the sideways ice cream cone thingy...
- 01:09
...and we have x is greater than negative 3.
- 01:11
So yep, the answer is indeed D.
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